Lens and lamp body assembly



May 18, 1965 R. l. NAGEL LENS AND LAMP BODY ASSEMBLY 3 Sheets-Sheet 1 Original Filed Aug. 13, 1962 INVENTOR- ROBERT I. NAGEL BY 6 z E 5 ATTORNEY May 18, 1965 R. 1. NAGEL 3,134,590

LENS AND LAMP BODY ASSEMBLY Original Filed Aug. 13, 1962 3 Sheets-Sheet 2 INVENTOR.

ROBERT I. NAGEL ATTORNEY May 18, 1965 R. 1. NAGEL 3,184,590

LENS AND LAMP BODY ASSEMBLY Original Filed Aug. 13, 1962 3 Sheets-Sheet 3 INVENTOR. ROBERT I. NAGEL BY Z Al :ORNEY 3,18%,596 LEN AND LAMP RUDY ASSEMBLY Robert ll. Nagci, irohie, llii., assignor to Elastic Stop Nut Corporation of America, Union, Ni, a corporation of New Jersey Continuation of application Ser. No. 216,538, Aug. 13, 1962. This application June 12, 1964, Ser. No. 374,573 8 Qlaims. (Cl. ass-11.2)

The present invention relates generally to an electric lamp for use on motor vehicles, and more specifically pertains to a housing construction for such electric lamps.

This application is a continuation of an earlier application Serial No. 216,538, executed by Robert I. Nagel and filed August 13, 1962, now abandoned, for a Lens and Lamp Body Assembly.

lectric lamps which are employed on motor vehicles are usually subjected to a variety of ambient conditions such as severe temperatures, moisture and dust as Well as generally rough treatment such as vibration and shock resulting from jouncing and contact with foreign objects. One particular type of vehicle lamp known as a clearance light is used in quantity for marking various points on truck bodies. Many different constructions have been devised for clearance lights in an eiiort to simplify their fabrication as well as their operation while retaining all of the characteristics necessary to withstand the operating conditions encountered by such lights.

I have found that by taking advantage of the resilient nature of certain synthetic resins, I have been able to construct an easily assembled lamp housing having only two major component parts which are easily fabricated and readily assembled to form a clearance lamp housing having all of the desired characteristics for satisfactory operation. The housing is readily disassembled, when desired, for maintenance purposes.

It is an important object of the invention to provide a housing for an electric lamp, which housing has improved means for retaining the lens portion thereof in separable assembled relationship with the lamp body or base.

Another object of the invention is to provide an electric lamp housing having a simplified construction and being capable of economical manufacture.

Still another object of the invention is to provide an electric lamp housing having a resilient plastic base and a resilient plastic lens and having improved means for retainin the lens in separable assembled relationship with the base.

A further object of the invention is to provide an electric lamp housing capable of being fabricated economically in large quantities of uniform quality.

A still further object of the invention is to provide an improved clearance light housing.

The invention may be described briefly as providing in an electric lamp housing having component parts including a base and a lens readily assembled with the base and disassembled therefrom, means for maintaining the lens assembled with the base, the means comprising a continuous annular groove means in one of the component parts and a continuous annular projection means integral with the other of the component parts and projecting radially therefrom for engaging the groove means when the parts are in assembled relationship. First and second continuous annular resilient means, each integral with one of the component parts are included, one of the means carrying the groove means and the other of the means carrying the projection means, the first and second annular means normally projecting axially from their respective component parts and overlapping with one another when the parts are in assembled relationship for flexing radially away from one another and from their respective normal positions in response to axial movement of t e parts toward assembled relationship and returning toward their normal positions upon completion of such assembly such that the projection means will engage the groove means with sufficient interlocking force to maintain the parts in assembled relationship with at least one of the first and second annular means near enough to its normal position to preclude the maintenance of excessive deflection in that one means while the parts remain in assembled relationship.

The invention will be more clearly understood and additional objects and advantages thereof will become apparent in the following detailed description of an embodiment of the invention illustrated in the accompanying drawings in which:

FIGURE 1 is a perspective view of component parts of a clearance light constructed in accordance with the invention;

FIGURE 2 is a cross-sectional view taken along line 22 of FIGURE 1;

FIGURE 3 is a perspective view of an assembled clearance light housing constructed of the component parts illustrated in FIGURE 1;

FIGURE 4 is a cross-sectional view taken along line 4d of FIGURE 3; and

FIGURE 5 is an enlarged fragmentary cross-sectional view diagrammatically illustrating the assembly of a lens and a base in the clearance light housing of FIGURE 3.

Referring now to the drawings and to FIGURES 1 through 4 in particular, a clearance light housing is designated generally at lull and comprises a lens 12. and a base 14-. The base 14 is designed to support a pair of sockets each having a light bulb therein, the bulbs and sockets not being shown. The sockets are supported in one or more brackets (not shown) which are suitably secured on the base 14 as, for example, by a rivet passing through perforation 16 in the base. It is desirable, for obvious reasons, that such brackets and the surface of base 14 surrounding them have good light reflecting characteristics. The openings 22 are provided to receive fasteners for securing the base 14 to the body or frame of the vehicle. An aperture 24 and a recess 28 at the lower edge of the base 14 serve to accommodate an electrical conductor for carrying current to the light bulbs.

In clearance light housings and indeed in many other similar housings for electric lamps, it is desirable to have one component part such as the lens 12 secured to another component part such as the base 14 in such a way that they may be separated without damage to either component part but at the same time to have them secured to each other tightly enough to preclude the possibility that they will become separated inadvertently. Thus, in a clearance light such as it the lens l2 ought to be removable to permit replacement of bulbs but should be hold tight enough to prevent it from being loosened by vibration or by other means except when force is applied intentionally to bring about such separation.

To this end, as best seen in FIGURES l, 2 and 4, the base 14 a short distance inwardly from its outer edge is provided with an integral upstanding continuous annular flange 2b which norm-ally projects axially from the base and carries a projection in the form of an annular bead or rim 32 oiiset laterally, or radially, outwardly from flange and having a convex outer surface 34 which curves outwardly adjacent the flange and then slightly inwardly again.

The :base 14 is a unitary construct-ion and is preferably fabricated of a molded plastic which provides a certain amount of resflience in flange 30 to render the flange laterally flexible and allow deflection radially inwardly away from its normal axial position for purposes which will be more fully explained later. A variety of stiflly flexible synthetic resins are suitable for the fabrication of base 14.

In order to cooperate with the base 14, the lens 12 is provided with a continuous annular skirt 40 normally projecting axially for overlapping with the flange 3b as best seen in FIGURES 3 and 4. A continuous annular groove 42 is formed in the skirt 4% and is so positioned therein as to cooperate with bead 32 of the flange 30 to maintain the lens and the base in assembled relationship. Lens 12 is preferably fabricated of a transparent plastic such as polymerized methyl methacrylate sold, for example, under the trademarks, Lucite and Plexi- :glas. Such a synthetic resin renders skirt 40 stifiiy flexible in a lateral direction and allows deflection of the skirt radially outwardly away from its normal position so as to permit assembly of the lens and the base into a suitable housing as will now be explained.

The assembly of the lens to the base is accomplished by moving the lens downwardly with respect to the base or toward the base of the housing as shown in FIGURE 4. A portion of the inner surface of the skirt 40 is beveled at 44 and has annular dimensions which are greater than those of the outer surface of the upper portion of the bead 32; hence, as the lens 12 is moved downwardly toward the base 14, no resistance to such movement is encountered until the rim of the lens is well below the rim of the head 32, whereupon pressure exerted downwardly upon the lens 12 relative to the base 14, the lens and the base being formed of a stiflly flexible resilient plastic, causes sufficient deflection of the skirt 40 and the flange 30 to radially contract the flange and dilate the skirt to permit the bead 32 to enter the groove 42 and seat itself therein as shown in FIGURE 4.

When this has occurred, a considerable force is re quired to separate the lens and the base. To facilitate the exertion of the required force, the base 14 midway each of its long sides is formed with slots for recesses 50. By inserting a coin or other like means in either of these slots 50 and twisting it, it is possible to apply snflicient force between the lens edge 52 and the base to force the bead 32 out of the groove 42, thereby disengaging and freeing the lens from the base. In point of fact, assembly of the lens and the base instead of taking place by a straight line movement as described above, generally tends to occur by a sort of pivotal movement similar to that which occurs when the two component parts are being separated.

With reference to FIGURES 3 and 4, it is further pointed out that the facing of flange 30 inwardly from the perimeter of base 14 is such that outer surface 54 of lens 12 in the assembly is approximately in alignment with the edge surface 56 of base 14 which has an inward slope from the bottom up which is approximately the same as that of lens surface 54. In addition to giving a pleasing appearance, this feature further aids in preventing the inadvertent separation of the lens 12 from the base 14. This results from the fact that the shoulder 58 formed on base 14 by the inward spacing of flange 30 thus confronts and underlies the edge 52 of lens 12 except at slots 51) in such a closely adjacent rela- .tion as to substantially preclude any application of force to the edge 52 which would tend to separate the lens 12 from the base 14 except at slots 50.

As indicated above, the light passing through lens 12 emanates from two bulbs and the bulk of light emanates directly from the filaments, thus reaching the inner surcf-ace of the lens at varying angles. In order to decrease the spread of the light emitted from the top and end surfaces of lens 12, the corresponding inner surfaces of the lens are provided with at least one and preferably a plurality of optical elements 60 shown in FIGURES 2 and 4 which, as indicated, continue downwardly on' the ends of the lens.

In order for the clearance light 10 to perform properly under the conditions encountered in service, it is essential that the bead 3 2 interiit properly with the groove 42 so that the engagement of the bead and groove will not only maintain the lens and base in assembled relationship, but will do so with the establishment of a seal at the mating surfaces tending to prevent the entry of dust and moisture into the housing and will do so without maintaining unduly large stresses in the mating component parts during service. In particular, it has been found that the transparent plastic materials employed for the lens should not be maintained under a great deal of stress in the assembly since such changes in temperature and the application of shocks to the lens have been tound to result in cracking of the lens during service. Thus, while the lens material allows relatively large defiections in skirt 40 during assembly in order to enable the skirt 48 to be overlapped with the flange 30 and permit bead 32 to enter groove 42, sustained large deflections in the skirt after assembly could result in excessive stresses and cracking of the lens. In addition, large deflections in the lens skirt during service can result in distortion of the optical elements in the lens with a concomitant reduction in the optical efliciency of the clearance light 10.

While FIGURES 2 and 4 show the positions of the flange 3t} and skirt 40 before and after assembly of'the base 14 and lens 12, FIGURE 5 depicts in phantom the flexing of the flange and the skirt during assembly of the component parts (as well as during disassembly) and illustrates the final position of the flange and the skirt when the component parts are in assembled relationship. In order to obviate any difliculties as a result of excessive stress in the assembled parts the invention contemplates minimizing the radial deflection in the assembled skirt and flange, and particularly in the skirt. Thus, the flange and skirt are made radially flexible to allow deflection away from one another and from their normal axial positions in response to axial movement of the lens into assembled relationship with the base, but the relative dimensions of the flange 39 with its bead 2 and the skirt 49 with its groove 42 permits the resiliency of these structures to return the flange and skirt back toward their normal positions. By allowing the skirt to return essentially to its normal, undeflected position after assembly of the lens and base, excessive deflection, and consequently excessive stress, is eliminated.

It is noted, however, that bead 32 should engage groove 42 with suificient interlocking force to retain the lens and base in assembled relationship and effect the necessary seal therebetween. Thus, some deflection in either the flange 30 or the skirt 40 should be maintained even after assembly of the lens and base. It has been found that by adjusting the wall thickness (the thickness measured in a radial direction) of the skirt and the wall thickness of the flange, most of the deflection can be absorbed by the flange which, by virtue of the material chosen for the base, is less susceptible to cracking from large deflections, even though these deflections may be maintained during service. Thus, while flange 30 is provided with a given wall thickness as seen at 70 in FIG- URE 5, the wall thickness is reduced in the vicinity of the bead 32 by the offset of portion 72 radially outwardly to enhance the radial flexibility of the flange at the bead. And, in fact, it may be discerned in FIGURE 5 that the flange 36 flexes to a greater extent in the vicinity of bead 32during assembly than at locations further away from the bead.

While the embodiment of the invention which has been illustrated and described is a housing for a clearance light,

it is to be understood that the invention is not limit d' to such structures and is applicable to a wide variety of other types of lamp housings, particularly those designed for use on motor, vehicles. Thus, in addition to housings 5 for clearance lights, the invention is applicable to other similar types of housings such as stop lamps and tail lamps, especially those used on trucks.

It may also be noted that in the embodiment shown, the projecting or convex surface forming a portion of the means for removably securing the two component parts together is on an outwardly facing surface and the cooperating groove is on an inwardly facing surface. This arrangement may be reversed, however, within the scope of the invention so that the projecting rounded surface faces inwardly and the cooperating groove faces outwardly. Thus, the bead 32 may be provided on the inner face of the skirt 4% of the lens 12 and the cooperating groove 42 may be formed in the outer face of the upstanding flange 30 of the base 14. In either case it is desirable to provide a beveled surface such as the surface td or its equivalent on the part in which the groove is formed and in a position such that the initial engagement of the parts occurs between the beveled surface and the projecting convex surface on the other part. In such a case the wall thickness-es of the skirt and the flange, respectively, would still be adjusted to permit the flange to be readily flexed so as to minimize a deflection of the skirt after assembly of the component parts is complete.

The configuration of the projection and of the cooperating groove may also be varied within the scope of the invention. For example, very satisfactory results are obtained when the cooperating groove is formed with a ll-shape instead of the rounded concave shape shown. Also, while the convex curved form of the projection surface is decidedly preferable to other configurations, it may be varied provided at least one of either the projection or the groove is so shaped that pressure exerted to separate the parts axially forces the projection out of the groove.

Many of the advantages of the present invention will be apparent from the foregoing description. The outstanding advantage is that electric lamp housings are provided in which the lens and base are separable but are, however, held together tightly enough to avoid inadvertent separation without the use of separable fasteners and at a cost relatively much less than that of comparable articles heretofore known. In accordance with the present invention it is also possible in such a lamp housing to provide in the joint a suitable degree of sealing effectiveness. Thus, the invention contemplates a simple, two component part lamp housing which is both dependable and effective in use.

it is apparent that many widely different embodiments of the invention may be made without departing from the spirit and scope thereof and, therefore, it is not intended to limit the invention except as indicated in the appended claims.

The embodiments of this invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an electric lamp housing having component parts including a base and a lens readily assembled with the base and disassembled therefrom, means for maintaining the lens assembled with the base, said means comprising:

a continuous annular groove means in one of said component parts;

a continuous annular projection means integral with the other of said component parts and projecting radially therefrom for engaging said groove means when the parts are in assembled relationship;

first and second continuous annular resilient means each integral with one of said parts, one said means carrying said groove means and the other of said means carrying said projection means, said first and second annular means normally projecting axially from their respective component parts and overlapping with one another when the parts are in assembled relationship for flexing radially away from one another and from their respective normal positions in response to axial movement of said parts toward said assembled relationship and returning toward said normal positions upon completion of such assembly such that the projection means will engage the groove means with sufficient interlocking force to maintain said parts in assembled relationship with at least one of said first and second annular means near enough to its normal position to preclude the maintenance of excessive deflection in said one means while the parts remain in assembled relationship.

2. A readily assembled and disassembled electric lamp housing comprising:

a unitary base of resilient plastic including a continuous annular axially projecting radially deflectable flange means integral with the base;

a unitary lens of resilient plastic including a continuous annular axially projecting radially deflectable skirt means integral with the lens for overlapping with the flange means when the base and the lens are in assembled relationship;

a continuous annular groove means in one of said overlapping means;

a continuous annular projection means integral with the other of said overlapping means and projecting radially therefrom for engaging said groove means when the base and the lens are in assembled relationship;

said flange means normally projecting axially from the base and being defiectable radially from said normal position to effect radial contraction thereof and said skirt means normally projecting axially from the lens and being defiectable radially away from said normal position to efiect radial dilation thereof for allowing radial deflection of said flange means and said skirt means away from one another and from their respective normal positions in response to axial movement of the base and the lens toward assembled relationship and return toward said normal positions upon completion of such assembly such that the projection means will engage the groove means with sufficient interlocking force to maintain said lens and base in assembled relationship with at least said skirt means near enough to its normal position to preclude the maintenance of excessive dilation thereof while the lens and the base remain in assembled relationship.

3. An electric lamp housing of claim 2 wherein said groove means is in said skirt means and said projection means is integral with the flange means and projects radially outwardly to engage said groove means when the base and the lens are in assembled relationship.

4. A readily assembled and disassembled electric lamp housing comprising:

a unitary base of molded stiflly flexible resilient synthetic resin including a continuous annular flange integral with the base, said flange normally projecting axially from the base and being deflectable radially away from said normal position to effect radial contraction thereof;

a unitary lens of molded methyl methacrylate resin including a continuous annular skirt integral with the lens, said skirt normally projecting axially from the lens and being resiliently deflectable radially away from said normal position to effect radial dilation thereof, the skirt overlapping with the flange when the base and the lens are in assembled relationship;

a continuous annular groove in the skirt;

a continuous annular projection integral with the flange and projecting radially therefrom for engaging said groove when the base and the lens are in assembled relationship;

at least one optical element in said lens;

said flange and skirt being radially deflectable away from one another and from their respective normal positions in response to axial movement of the base and the lens toward assembled relationship and returnable toward said normal positions upon completion of such assembly such that the projection will engage the groove with sufficient interlocking force to maintain said lens and base in assembled relationship with at least said skirt near enough to its normal position to preclude the maintenance of excessive dilation thereof and distortion of said optical element while the lens and base remain in assembled relationship.

5. In an electric lamp housing having component parts therefrom at a given axial location for engaging said groove when the base and the lens are in assembled relationship;

said flange and skirt portions being resiliently flexible radially away from one another and from their respective normal positions in response to axial move ment of the base and the lens toward assembled relationship and returnable toward said normal positions upon completion of such assembly such that the projection will engage the groove with sufiicient interlocking force to maintain said lens and base in assembled relationship, the given radial wall thickness of the flange portion being so limited in the vicinity of said axial location as to increase the radial flexibility of the flange portion in said vicinity to :allow said skirt portion to return near enough to its normal position to preclude the maintenance of including a base and a lens readily assembled with the base and disassembled therefrom, means for maintaining the lens assembled with the base, said means comprising:

a first continuous annular portion of stifliy flexible resilient material integral with one of said component par-ts and normally projecting axially therefrom, said first portion having a given radial wall thickness and being deflectable radially away from said normal position to effect radial contraction thereof;

a second continuous annular portion of stiflly flexible resilient material integral with the other of said component parts and normally projecting axially therefrom, said second portion having a given radial wall thickness and being deflectable radially away from said normal position to effect radial dilation thereof, said second portionoverlapping said first portion when the component parts are in assembled relationship;

a continuous annular groove in one of said overlapping portions at a given axial location;

a continuous annular projection integral with the other of said overlapping portions and projecting radially therefrom at a given axial location for engaging said groove when the component parts are in assembled relationship;

excessive dilation of the skirt portion while the lens and base remain in assembled relationship.

7. An electric lamp housing of claim 6 wherein said groove is in the skirt portion of the lens and said projection is integral with the flange portion of the base and projects radially outwardly to engage the groove when the base and the lens are in assembled relationship, the limited radial wall thickness of the flange portion being in the vicinity of the projection.

8. A readily assembled and disassembled electric lamp housing comprising:

a unitary base of molded stiifly flexible resilient synthetic resin including a continuous annular flange integral with the base and normally projecting axially therefrom, said flange having a given radial wall thickness and being deflectable radially away from said normal position to effect radial contraction thereof;

a unitary lens of molded methyl methacrylate resin including a continuous annular skirt integral with the lens and normally projecting axially therefrom, said skirt being deflectable radially away from said said first and second portions bei radially fle ibl normal position to effect radial dilation thereof, the away from one another and from their respective skirt overlapping with the flange when the base and normal positions in response to axial movement of the lens are in assembled relationship; said parts toward assembled relationship and returna continuous annular groove in the skirt at a given axial able toward said normal positions upon completion location;

a continuous annular projection integral with the flange of such assembly such that the projection will engage the groove with sufflcient interlocking force to maintain said component parts in assembled relationship, the given radial wall thickness of one of said portions being so limited in the vicinity of said axial location as to increase the radial flexibility of that portion in said vicinity to allow the other of said portions to return near enough to its normal position to preclude the maintenance of excessive deflection in that portion while the parts remain in assembled relationship.

6. A readily assembled and disassembled electric lamp housing comprising:

a unitary base of resilient plastic including a continuous annular flange portion integral with the base and normally projecting axially therefrom, said flange portion having a given radial wall thickness and being deflectable radially from said normal position to effect radial contraction thereof;

a unitary lens of resilient plastic including a continuous annular skirt portion integral with the lens and normally projecting axially therefrom, said skirt portion being deflectable radially away from said normal position to effect radial dilation thereof, the skirt portion overlapping with the flange portion. when and projecting radially therefrom at a given axial location for engaging said groove when the base and the lens are in assembled relationship;

at least one optical element in said lens;

said flange and skirt being resiliently flexible radially away from one another and from their respective normal positions in response to axial movement of the base and the lens toward assembled relationship and returnable toward said normal positions upon completion of such assembly such that the projection will engage the groove with suflicient interlocking force to maintain said lens and base in assembled relationship, the given radial wall thickness of the flange being so limited in the vicinity of said axial location as to increase the radial flexibility of the flange in said vicinity to allow said skirt to return near enough to its normal position to preclude the maintenance of excessive dilation of the skirt portion and distortion of the optical element while the lens and base remain in assembled relationship.

References Cited by the Examiner UNITED STATES PATENTS the base and the lens are in assembled relationship; 7 2 322 233 a continuous annular groove in one of said overlapping 3114182 12/63 Trauma, a;

portions at a given axial location; a a continuous annular projection integral with the other of said overlapping portions and projecting radially NORTON ANSHER, Primary Examiner. 

1. IN AN ELECTRIC LAMP HOUSING HAVING COMPONENT PARTS INCLUDING A BASE AND A LENS READILY ASSEMBLED WITH THE BASE AND DISASSEMBLED THEREFROM, MEANS FOR MAINTAINING THE LENS ASSEMBLED WITH THE BASE, SAID MEANS COMPRISING: A CONTINUOUS ANNULAR GROOVE MEANS IN ONE OF SAID COMPONENT PARTS; A CONTINUOUS ANNULAR PROJECTION MEANS INTEGRAL WITH THE OTHER OF SAID COMPONENT PARTS AND PROJECTING RADIALLY THEREFROM FOR ENGAGING SAID GROOVE MEANS WHEN THE PARTS ARE IN ASSEMBLED RELATIONSHIP; FIRST AND SECOND CONTINUOUS ANNULAR RESILIENT MEANS EACH INTEGRAL WITH ONE OF SAID PARTS, ONE SAID MEANS CARRYING SAID GROOVE MEANS AND THE OTHER OF SAID MEANS CARRYING SAID PROJECTION MEANS, SAID FIRST AND SECOND ANNULAR MEANS NORMALLY PROJECTING AXIALLY FROM THEIR RESPECTIVE COMPONENT PARTS AND IN OVERLAPPING WITH ONE ANOTHER WHEN THE PARTS ARE IN ASSEMBLED RELATIONSHIP FOR FLEXING RADIALLY AWAY FROM ONE ANOTHER AND FROM THEIR RESPECTIVE NORMAL POSITIONS IN RESPONSE TO AXIAL MOVEMENT OF SAID PARTS TOWARD SAID ASSEMBLED RELATIONSHIP AND RETURNING TOWARD SAID NORMAL POSITIONS UPON COMPLETION OF SUCH ASSEMBLY SUCH THAT THE PROJECTION MEANS WILL ENGAGE THE GROOVE MEANS WITH SUFFICIENT INTERLOCKING FORCE TO MAINTAIN SAID PARTS IN ASSEMBLED RELATIONSHIP WITH AT LEAST ONE OF SAID FIRST AND SECOND ANNULAR MEANS NEAR ENOUGH TO ITS NORMAL POSITION TO PRECLUDE THE MAINTENANCE OF EXCESSIVE DEFLECTION IN SAID ONE MEANS WHILE THE PARTS REMAIN IN ASSEMBLED RELATIONSHIP. 